I've been asked many times about how to start writing for Paizo, either on Pathfinder or Starfinder. I figured I would make a definitive post about the subject! While there isn't an exact step-by-step process to this, I think this covers most bases and should help you get well on your way with Paizo (or Wizards of the Coast or any other game company)!
Just Start Writing
The most important thing that comes to mind is to just start writing something. This can be details for your homebrew campaign, the backstory of an NPC, a new monster for your game, a magic item you want to hand out to your players, or even a homebrew class! In fact, it doesn't even need to be gaming related (though it probably should be), as long as you're doing some writing. You need practice with writing. I'm not just talking about notes in a notebook or a document on your computer. It's gotta be proper writing. Write full paragraphs. Follow basic grammar rules and try to clean up the writing afterward so it's a bit presentable. If you're going to be writing for games, you're going to need to build up the habits and disciplines that come with writing.
Writing can take a lot of forms, mind you. If you want to write everything by hand and then transcribe it into a Google Doc later, that's great. If you want to open a Word doc and just go at it until your fingers bleed and then come back later to knock it all into shape, you're golden. If you'd rather dictate to your phone and clean it up afterward. Awesome. What matters is that you find something that works for you and gets you to the point where material is being written.
Finally, don't just write one or two things. Write a bunch. Fall in love with some of it, get upset at other bits, feel indifferent or unsure about the rest. It's natural. What's important is that you're doing it and are doing it enough so you get a good feel for it. You don't need to write entire novels, but you should at least write more than just two pages. Once you have a good feel for writing, you can move on to the next step.
Create a Portfolio
Ideally, you wrote a lot of gaming material back in the last step. If you didn't, I hope you've developed a good habit for writing so you can now do some of that game writing. Once you have a bit of it—it can just be a handful of things—you're going to put it somewhere accessible to the public. This can and probably should be a blog or similar website. You need somewhere you can point potential employers to so they can see your work and your skills. If someone can't see anything you've written, they can't judge any of your work and probably will never want to give you work since they don't know the quality of your writing.
While your portfolio can showcase all of your work, I do recommend a few specific showcase pieces. Specifically, you want something short and sweet that shows off your chops. What these chops might be are for your to decide. If you're more focused on mechanics and game options, you probably want something like some feats, cool magic items, or spells. If you're interested in worldbuilding, writing a few short entries on specific adventuring sites or NPC backgrounds is good. If you want to write fiction, get some short stories in there, but make sure it's based on the setting you want to write for. If you want to do both mechanics and worldbuilding, my recommendation is a monster. A simple monster writeup can show both mechanical understanding and gives you a bit of space for worldbuilding. Paizo can fit a monster one one page and sell the idea of the monster, how it works, and fun things it can do in the game in that single page. If you can do that too, you'll be set!
It can be scary to put your work out in the public sphere. I get it! Two things to keep in mind: First, this fear of public scrutiny is something you'll need to learn to deal with if you're going to be writing material that's going to be used by hundreds or thousands of players, so this is good practice. Second, it's very unlikely anyone will actually find your blog at this point in your career. You're totally safe. If you're worried about what people will think of your writing (and you probably should be since you want employers to give you work), use this as an opportunity to clean up your work. Reread it. Edit it some more. If you feel there's literally nothing wrong with it, you're probably wrong and should have a friend look at it since it's very easy to gloss over stuff when you're too familiar with it. Once you're ready, we're moving on to the next step.
Write to Your Game
Tricked you! This should have actually been step 2, but jumping into the water that is getting your stuff up somewhere is more important in my eyes, at least in these initial stages. Yes, you've written game stuff and might even have it online somewhere now, but there's a decent chance that it's not as good as it could be and this step will help you get it there.
You're likely wanting to write for a specific game or company (Pathfinder, Starfinder, or Paizo most likely based on this headline). Writing for a game means learning a lot of technical writing, specifically with regard to mechanics. Every roleplaying game has it's very specific selection of formatting and styles for its rules and learning these will go a long way both in getting attention and in the work proper in the future. Do your best to replicate existing official material for the game you want to write for as much as you can. Take a note of when things are bolded or italicized or the order of listings in a monster stat block. Pathfinder has a distinction between "making" and "attempting" specific types of checks. Do you know what these distinctions are? If not, you should learn them and make sure you're using it correctly in your writing. The more you can closely replicate the existing material, the more you'll get a feel for the game's specific style and it will go a long way to prove that it's worth taking a shot on you. If your material uses language and formatting that matches Dungeons and Dragons, but you want to work on Pathfinder, that material won't do you any good (for the most part). Write for the game you want to be paid to write for!
There are lots of little things it's easy to miss with a big ruleset like Pathfinder, but the more you can learn and prove that you know your stuff, the better off you'll be. We're less likely to hire someone who doesn't seem to recognize that spell names are italicized and not capitalized. If you're missing some of the bigger, obvious stuff, it's harder to sell yourself as someone who knows the game. This also applies to setting and worldbuilding writing. Pathfinder and Dungeons and Dragons have two similarly named planes: the Plane of Shadow and the Shadow Plane. Which plane belongs to which game? Getting these details right is just as important as knowing whether or not you need a period at the end of the "Trigger" line of a feat. (Spoilers: You do. Triggers are complete sentences.)
Reaching Out for Work
Now comes the time to bring it all together. You have some writing under your belt, somewhere to show it off, and of course, you spruced it up to make it look like the game you want to write for. Now you need to get in contact with someone that can give you work. Unfortunately, it's unlikely that your first writing job will be with Paizo (or your prospective employer of choice). Mine wasn't! Instead, I recommend looking at some of the companies doing third-party work for Pathfinder and Starfinder. A few that come to mind are Eldritch Osiris Games and Team+.
Once you find someone to get in touch with this potential employer. You're likely doing this through email, so here's some things you'll want in your email. Do a brief intro, talk about your experience, and note the things you're interested in writing (class options, spells, monsters, adventures, setting lore, fiction, etc.). Include any specific expertise that you think might be relevant. Knowing things like any degrees you have (whether writing-related or not), keen interests, relevant hobbies, and so on. Finally, and most importantly, give them a writing sample. This writing sample should be a link to the strongest piece in your portfolio, the one that best showcases your skills and sells your quality in a quick read. If you're really fancy, you can grab that piece and throw it into a PDF and attach it to the email while also including a link to your greater portfolio. If all goes well, the employer will like your sample and offer you some work. If it goes less well, they might say there's no work at the moment, but to try again later. If it goes worse, you might just get a rejection. If it goes worst, they reject you rudely and you realize this is probably not someone you should be working with.
If you get the work, though, that's great! Make sure to meet your deadlines, follow the assignment (if you were tasked with new ice spells, don't throw in a random ice archetype or a fire spell cause you think it would be cool), follow the formatting and style requirements, and don't be afraid to ask questions! If you need a bit more insight or clarity on a part of the assignment, ask for it. It's better to do a bit more questioning upfront than turn in poor work that's going to take a lot of effort to fix.
Once you get through the assignment, ask your employer if you can add it to your credits in your portfolio. It might take some time before you can, but once you have the greenlight, get that credit up there! You want to be able to note that you did it, since it can help you get more work in the future. Then, see if you can get another assignment. Once you have two or three assignments under your belt, see about reaching out to Paizo or your company of choice. You can come to them with a strong writing sample, a portfolio, and list of prior credits, which makes you a much more enticing potential author for work. If you're good and you're lucky, you'll get an assignment!
There it is! How to get started writing for Paizo. There's a whole lot that happens during all of those steps, but it's what I tell everyone to do if they want to get started writing for us. Good luck and good writing!